(1) Field of the Invention
The present invention relates to an adhesive tape joining apparatus used when an adhesive tape is joined to a curved workpiece such as a door sash of an automobile.
(2) Description of the Related Art
In recent years, in a manufacturing process of an automobile, in place of black coating processing on a door sash, a technology to join a black adhesive tape has been developed. As this joining technology, an adhesive tape joining apparatus (an adhesive tape joining jig) has been suggested. Herein, an adhesive tape from which a separator is separated is elastically pressed against a tape joining face with a joining roller to be joined thereto while guiding and moving this adhesive tape joining apparatus on hand along a workpiece (refer to JP-A 2001-115117).
This adhesive tape joining apparatus (adhesive tape joining jig) is provided with four bottom guide rollers to be engaged on back and forth and right and left of a bottom face that is a tape joining face of the workpiece and four side guide rollers to be engaged on back and forth two places of the right and left side faces of the workpiece at its base. In addition, a single pressing roller to be elastically pressed against the upper face of the workpiece is mounted on a pressing lever that is pivotally connected to the base. Then, a bottom guide roller group and the pressing roller sandwich the workpiece vertically so as to hold the posture of the adhesive tape joining apparatus with respect to the workpiece. At the same time, by engaging the side guide rollers from right and left of the workpiece, positioning in a right and left direction of the adhesive tape joining apparatus with respect to the workpiece has been made.
Thus, moving the adhesive tape joining apparatus of which position and posture are determined along the workpiece due to the guidance of engagement by the roller group, the adhesive tape is elastically pressed against the bottom of the workpiece by an elastic roller arranged at the rear end of the base to be joined thereto. In addition, the adhesive tape to be supplied is curved and guided ahead of the elastic roller. In this case, the separator is separated to be fed forward in a joining moving direction through a gap formed between the base and a sliding plate.
However, the conventional apparatus has the following problems.
In other words, the suggested adhesive tape joining apparatus employs guiding means using four bottom guide rollers to be engaged with the bottom face of the workpiece and two pairs of side guide rollers that are engaged with the right and left side faces of the workpiece, respectively, so that there are many engagement guide operational places. Therefore, a function to hold the posture of the adhesive tape joining apparatus and a function to determine the position thereof with respect to the workpiece are sophisticated. These functions can be sufficiently practiced for a linear workpiece. However, the elastic roller to press the adhesive tape against the tape joining face is arranged at a rear part of the guide roller group, so that this involves a problem such that the appropriate joining is not performed to the workpiece having a curved part.
In other words, in the case that this adhesive tape joining apparatus is moved forward along a workpiece having a curved portion, when the guide roller group passes through, for example, the curved portion shaped in a mountain, the posture of the apparatus will be determined depending on the direction of the workpiece that is located over the curved portion. Therefore, since the elastic roller behind the guide roller group is located in front of the curved portion yet, the elastic roller will come close to the workpiece. Accordingly, in front of the curved portion, the elastic roller will be elastically transformed more than the normal case to be pressed against the tape joining face. As a result, the adhesive tape will be locally pressed by a large pressure and a stretch and a crease are generated on the adhesive tape.
In addition, there is a limit in the elastic transformation of the elastic roller, so that the apparatus cannot follow the sharp curve of the workpiece. In other words, the suggested adhesive tape joining apparatus can be effectively used for the workpiece having a linear or a gentle curved portion. However, this involves a problem such that the apparatus cannot continuously join the tape on the workpiece having a relatively sharp curved portion.
In addition, in the suggested adhesive tape joining apparatus, the separated separator is discharged forward in a joining moving direction of the adhesive tape joining apparatus. Therefore, in the case of carrying out the joining processing on the horizontally long bottom face of the workpiece, even if the separated separator moves forward in a moving direction of the adhesive tape joining apparatus, it is not obstructive to the forward moving because it hangs down downward by its own weight. However, in the case of performing the joining processing on the longitudinal directed place in the workpiece, the separator moved forward in the moving direction of the adhesive tape joining apparatus is obstructive to the forward moving. Accordingly, this involves a disadvantage such that the attention to the adhesive tape joining operation gets distracted due to the operation to wave aside the separator or the joining moving speed is lowered so as to deteriorate finish of joining.